In a conventional vapor compression refrigerating apparatus, for example, as disclosed in Japanese Patent No. 2540738, a component (a condenser) of a refrigerating cycle is commonly used to form Rankine cycle, waste heat of an automotive engine (a heat generating device) is collected as driving force by an expansion device, which is commonly used as a compressor device, and the collected driving force is applied (returned) to the engine.
The waste heat of the engine is also used as a heating source for a heating operation, by supplying the waste heat to a heater of a heater circuit.
An operating rate of an engine is set at a lower value, when a hybrid vehicle, which has been becoming popular in recent years, is running at a low speed. As a heat amount (waste heat) generated in the engine is small, it is a problem in that a sufficient amount of the waste heat, in particular in a winter season, can not be supplied from the engine to the heater as the heating source. It is, therefore, necessary to operate the engine at the low speed running of the hybrid vehicle in order to obtain the heating source for the heater, even at sacrifice of a fuel consumption ratio.
In an ordinary vehicle, an amount of waste heat from the engine becomes smaller, as a result of developments for high-efficiency engines. A similar problem, in running short of the heating source for the heater, occurs in the ordinary vehicle, as in the hybrid vehicle. In the ordinary vehicle, for example, a PTC heater is provided to make up a deficit of the heat energy. However, such a device is high in cost.